Process for producing 1, 1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane

ABSTRACT

A process for production of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane which comprises reacting phenol with 3,3,5-trimethylcyclohexanone in the presence of an acid catalyst, separating the resulting phenol adduct crystals of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane from the resulting reaction mixture, and removing the phenol from the phenol adduct crystals, wherein the phenol adduct crystals are dissolved in a crystallization solvent comprising an aromatic hydrocarbon solvent and water, crystallizing the crystals of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane out of the crystallization solvent, and collecting the crystals by filtration at a temperature of 40–60° C.

TECHNICAL FIELD

The invention relates to a process for production of1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (referred to as“BPTMC” hereinafter). More particularly, the invention relates to aprocess for production of BPTMC by an acid condensation reaction ofphenol with 3,3,5-trimethylcyclohexanone (referred to as “TMC”hereinafter) wherein phenol adducts crystals of BPTMC obtained as thereaction product are crystallized out of a crystallization solvent andcollected by filtration thereby providing high purity BPTMC which isremarkably reduced in the amount of not only residual phenol but alsotrace impurities of sodium, chlorine and sulfur in a stable manner.

BACKGROUND ART

In recent years, BPTMC is used as raw materials for the production ofoptical products such as optical disks, as well as synthetic resins foroptical use such as polycarbonate resins for optical use. In order tosupply BPTMC to this use, it is demanded to produce uncolored highpurity BPTMC which is free of by-products, and besides free of highboiling point by-products or colored by-products derived frompurification processes for the obtained reaction product and residualphenol or trace impurities such as sodium in high selectivity and inhigh yield in an industrially stable manner.

A variety of processes for the production of BPTMC are already known.According to one of such processes, phenol is reacted with TMC in thepresence of an acid catalyst, and after the completion of the reaction,the resulting reaction mixture is neutralized, followed by removingwater therefrom and cooling to crystallize phenol adduct crystals ofBPTMC and collecting the crystals by filtration. The adduct crystals arethen treated to remove phenol therefrom to provide BPTMC. In order toremove phenol from the phenol adduct crystals of BPTMC, distillation orevaporation processes are usually employed. However, these processeshave a fear that the resultant BPTMC is thermally deteriorated andundesirably colored.

For instance, phenol is reacted with TMC using hydrogen chloride gas asan acid catalyst and an alkyl mercaptan as a promoter in the presence ofan inactive organic solvent or in the absence of a solvent and thenphenol remained unreacted is removed from the reaction mixture by steamdistillation, as described in Japanese Patent Application Laid-open No.2-88634. It is also described therein that, after the reaction, water isadded to the reaction mixture, and then an alkali to neutralize thereaction mixture, followed by heating, cooling and removing an aqueousphase, thereby obtaining the desired BPTMC as residue.

A further process is known, as is described in Japanese PatentApplication Laid-open No. 8-505644. According to the process, phenol isreacted with TMC using hydrogen chloride gas as a catalyst and an alkylmercaptan such as octanethiol as a promoter. After the reaction, wateris added to the reaction mixture to form a slurry, and the slurry isfiltered to provide 1:1 adduct crystals of BPTMC and phenol, and thenadduct crystals are broken up in warm water or in an aromatichydrocarbon solvent such as toluene to remove phenol therefrom, therebyproviding the desired BPTMC.

However, nothing has been known how to obtain high purity BPTMC in astable manner by removing phenol advantageously from phenol adductcrystals of BPTMC.

On the other hand, in respect of 2,2-bis(4-hydroxy-phenyl)propane(referred to as “bisphenol A” hereunder), some processes forpurification, in particular, those for production of high puritybisphenol A by removing phenol from phenol adduct crystals of bisphenolA are already known. For example, Japanese Patent Application Laid-openNo. 4-29947 describes a process as follows. Phenol adduct crystals ofbisphenol A are dissolved in a mixed solvent of phenol and an aromatichydrocarbon and then crystallized out of the solvent to provide highpurity product of bisphenol A.

A further process for production for high purity bisphenol A is alsoknown, as is described in Japanese Patent Application Laid-open No.5-294871. According to the process, phenol adduct crystals of bisphenolA are dissolved in water and then cooled to crystallize bisphenol A outof the water, followed by recryatallization out of an aromatichydrocarbon solvent.

However, it is difficult to predict the behavior of production of BPTMCby a condensation reaction of TMC which is an alicyclic ketone havingthree methyl groups in the molecule with phenol based on the behavior ofproduction of bisphenol A by a condensation reaction of acetone andphenol. As a matter of fact, nothing has been known how to obtain highlypurified product of BPTMC which is remarkably reduced in the amount ofnot only residual phenol but also trace impurities of sodium, chlorineand sulfur from phenol crystals of BPTMC in high yields and in a stablemanner.

The invention has been accomplished to solve such problems as involvedin the known processes for the production of BPTMC by an acidcondensation reaction of phenol and TMC.

Therefore, it is an object of the invention to provide a process forproduction of BPTMC advantageously in an industrial manner in whichphenol adduct crystals of BPTMC obtained as the reaction product arecrystallized from a crystallization solvent to provide highly purifiedproduct of BPTMC which is remarkably reduced in the amount of residualphenol and trace impurities of sodium, chlorine and sulfur.

SUMMARY OF THE INVENTION

The invention provides a process for production of1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane which comprisesreacting phenol with 3,3,5-trimethylcyclo-hexanone in the presence of anacid catalyst, separating the resulting phenol adduct crystals of1,1-bis(4-hydroxy-phenyl)-3,3,5-trimethylcyclohexane from the resultingreaction mixture, and removing the phenol from the phenol adductcrystals, wherein the phenol adduct crystals are dissolved in acrystallization solvent comprising an aromatic hydrocarbon solvent andwater, crystallizing the crystals of1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclo-hexane out of thecrystallization solvent, and collecting the crystals by filtrating at atemperature of 40–60° C.

BEST MODE FOR CARRYING OUT THE INVENTION

According to the invention, phenol is reacted with TMC in the presenceof an acid catalyst (reaction step), and after the completion of thereaction, an aqueous solution of an alkali is added to the resultingreaction mixture to neutralize it while it is heated so that theresulting phenol adduct crystals of BPTMC are dissolved in the reactionmixture to form a solution. The solution is then cooled to crystallizethe adduct crystals out of the solution and the crystals are collectedby filtration (primary crystallization and filtration step).

The adduct crystals are added to a crystallization solvent composed ofan aromatic hydrocarbon solvent and water and the mixture is heated to atemperature of 100–130° C., preferably under an increased pressure of0.2–0.4 MPa to dissolve the adduct crystals in the crystallizationsolvent.

The crystallization solvent usable is not specifically limited so longas it dissolves BPTMC when the solvent is heated whilst the solvent hasa reduced solubility of BPTMC when the solvent is cooled. However, anaromatic hydrocarbon solvent having a relatively low boiling point ispreferred, such as benzene, toluene, xylene or ethylbenzene, among whichtoluene is most preferred.

The crystallization solvent is usually composed of 55–75% by weight,preferably 60–70% by weight of aromatic hydrocarbon solvent. Thecrystallization solvent is used usually in an amount of 150–400 parts byweight, preferably 200–300 parts by weight, in relation to 100 parts byweight of adduct crystals. When the crystallization solvent is used inan amount of more than 400 parts by weight in relation to 100 parts byweight of adduct crystals, the volume efficiency in the purificationoperation is low while when the crystallization solvent is used in anamount of less than 150 parts by weight in relation to 100 parts byweight of the adduct crystals, it is difficult to remove sufficientlyresidual phenol and trace impurities from the resulting BPTMC.

In this way, the residual phenol is easily removed from BPTMC by usingthe aromatic hydrocarbon solvent as a crystallization solvent, and inaddition, the solubility of BPTMC in the crystallization solventincreases to improve the volume efficiency in the purification procedureby using water in combination with the aromatic hydrocarbon solvent.

According to the invention, as described above, after the adductcrystals are dissolved in the crystallization solvent, the water layeris separated from the resulting mixture by liquid—liquid separation orthe like, and the obtained oily layer is cooled to crystallize BPTMC,followed by collecting the crystals by filtration, thereby providinghigh purity BPTMC.

By employing such a purification procedure as mentioned above, singleoperation usually provides desired high purity BPTMC, however, ifnecessary, the operation is repeated twice or more. When the operationis repeated, the yield of the product decreases accordingly.

The crystals of BPTMC are crystallized out of the oily substance at atemperature of 70–100° C., preferably at a temperature of 80–90° C. Whenthe temperature is too low, the purification efficiency is low, whilewhen the temperature is too high, the purity of the product obtained islow.

According to the invention, the temperature at which the crystallizedBPTMC crystals are collected by filtration in order to keep the amountof the residual phenol in the BPTMC crystals at a low level stably. Thefiltration temperature is preferably in the range of 40–60° C., morepreferably in the range of 45–55° C. When the filtration temperature istoo low, the resulting BPTMC crystals contain undesirably not a smallamount of residual phenol, and the amount increases as the filtrationtakes a long time. When the filtration temperature is too high, theyield of desired BPTMC crystals is low.

The amount of the residual phenol in the crystals of BPTMC obtained isinfluenced also by the time of filtration, however, it is usuallydifficult to keep the time of filtration constant. According to theinvention, the filtration of crystals of BPTMC are crystallized at thetemperature as mentioned above so that the amount of the residual phenolin the crystals of BPTMC obtained is kept small stably if the time offiltration is varied.

INDUSTRIAL APPLICABILITY

As described above, according to the invention, phenol is reacted with3,3,5-trimethylcyclohexanone in the presence of an acid catalyst, andthe resulting phenol adduct crystals of BPTMC are crystallized out of acrystallization solvent comprised of an aromatic hydrocarbon solvent andwater, in particular, at a temperature of 40–60° C. Thus, high purityBPTMC is obtained stably in which the amount of residual phenol isremarkably small, and in addition, the amount of residual phenol is notvaried but substantially kept constant if the time of filtration isvaried. Furthermore, the crystals of BPTMC obtained are remarkablyreduced in the amount of trace impurities of sodium, chlorine andsulfur.

EXAMPLES

The invention is described in more detail with reference to examples,but the invention is not limited these examples.

Reference Example 1

188 g (2.0 mol) of phenol, 9.9 g of water and 0.5 g of 75% aqueoussolution of phosphoric acid were placed in a one liter capacityfour-necked flask provided with a thermometer, a dropping funnel, areflux condenser and a stirrer. The resulting mixture was adjusted at atemperature of 20° C. After the inside the flask was replaced bynitrogen gas, hydrogen chloride gas was introduced into the flask understirring. The gas composition in the flask was analyzed and the volumeconcentration of hydrogen chloride gas was adjusted at 80%.

21 g of 15% aqueous solution of sodium methyl mercaptide was addeddropwise to the mixture while the mixture was maintained at atemperature of 20° C., and then a mixture of 188 g (2.0 mol) of phenoland 70.0 g (0.5 mol) of TMC was added dropwise to the mixture over aperiod of three hours. After the addition, the reaction was furthercontinued at a temperature of 20° C. for anther three hours.

After the reaction, the resulting reaction mixture was analyzed byliquid chromatography. The production yield (mol of BPTMC produced/molof starting TMC used) was found to be 89.3%.

After the reaction, 18% aqueous solution of sodium hydroxide was addedto the reaction mixture so that it was neutralized to have a pH of 6.5while it was maintained at a temperature of 40–50° C. The thusneutralized reaction mixture was heated to a temperature of 95° C. sothat the formed phenol adduct crystals of BPTMC were dissolved therein.

Water was removed from the reaction mixture, and the resulting oilysubstance was cooled to a temperature of 30° C. to crystallize phenoladduct crystals of BPTMC. 177.9 g of the adduct crystals were collectedby filtration.

The adduct crystals were found to be composed of 133.4 g of BPTMC, 44.2g of phenol and 0.3 g of others by liquid chromatographic analysis. Theadduct crystals were further found to contain trace impurities of 170ppm of sodium (atomic absorption spectrometry), 200 pm of chlorine(inductively coupled plasma spectrometry) and 30 ppm of sulfur(inductively coupled plasma spectrometry).

Example 1

177.9 g of phenol adduct crystals of BPTMC obtained in Reference Example1, 266.9 g of toluene and 88 g of water were placed in one litercapacity autoclave provided with a thermometer, a manometer and stirrer.After the inside atmosphere of the autoclave was replaced by nitrogengas, the autoclave was closed, and then the inside was raised to atemperature of 120° C. with stirring to dissolve the adduct crystals inthe mixture. The stirring was then stopped, and the mixture was leftstanding for 30 minutes. The water layer was separated by liquid—liquidseparation, and the obtained oily layer was cooled to a temperature of50° C. so that BPTMC was crystallized, and immediately the oilysubstance was centrifuged to obtain BPTMC crystals while the oilysubstance was kept at a temperature of 50° C.

The thus obtained BPTMC crystals were dried at a temperature of 110° C.under a pressure of 20 mmHg for four hours to evaporate the solvent toprovide 111.5 g of high purity BPTMC crystals. The yield was 83.55%based on the adduct crystals.

The BPTMC crystals were found to have a purity of 99.9% and a phenolcontent of 100 ppm by liquid chromatographic analysis. The crystals werefurther found to contain trace impurities of 0.4 ppm of sodium (atomicabsorption spectrometry), 0.27 ppm of chlorine (inductively coupledplasma spectrometry) and 0.6 ppm of sulfur (inductively coupled plasmaspectrometry).

The analytical results of the high purity BPTMC crystals obtained areshown in FIG. 1 together with the time during which the oily substancewas held at the predetermined temperature (holding time) and thepredetermined temperature at which the crystals of BPTMC were filtrated(filtration temperature).

Example 2

129.4 g of phenol adduct crystals of BPTMC, 194.2 g of toluene and 97.1g of water were used and, after the oily substance obtained was held ata temperature of 50° C. for 16 hours, it was centrifuged at the sametemperature, and otherwise in the same manner as in Example 1, highpurity BPTMC crystals were obtained. The results are shown in Table 1.

Example 3

129.4 g of phenol adduct crystals of BPTMC, 194.2 g of toluene and 97.1g of water were used and, after the oily substance obtained was held ata temperature of 50° C. for 40 hours, it was centrifuged at the sametemperature, and otherwise in the same manner as in Example 1, highpurity BPTMC crystals were obtained. The results are shown in Table 1.

Comparative Example 1

129.4 g of phenol adduct crystals of BPTMC, 194.2 g of toluene and 97.1g of water were used and, after the oily substance obtained was held ata temperature of 30° C. for 22 hours, it was centrifuged at the sametemperature, and otherwise in the same manner as in Example 1, highpurity BPTMC crystals were obtained. The results are shown in Table 1.

Comparative Example 2

129.4 g of phenol adduct crystals of BPTMC, 194.2 g of toluene and 97.1g of water were used and, after the oily substance obtained was held ata temperature of 30° C. for 48 hours, it was centrifuged at the sametemperature, and otherwise in the same manner as in Example 1, highpurity BPTMC crystals were obtained. The results are shown in Table 1.

Comparative Example 3

129.4 g of phenol adduct crystals of BPTMC, 194.2 g of toluene and 97.1g of water were used and, immediately after the oily substance obtainedwas cooled to a temperature of 30° C., it was centrifuged, and otherwisein the same manner as in Example 1, high purity BPTMC crystals wereobtained. The results are shown in Table 1.

Comparative Example 4

129.4 g of phenol adduct crystals of BPTMC, 194.2 g of toluene and 97.1g of water were used and, immediately after the oily substance obtainedwas cooled to a temperature of 25° C., it was centrifuged, and otherwisein the same manner as in Example 1, high purity BPTMC crystals wereobtained. The results are shown in Table 1.

TABLE 1 Examples Comparative Examples 1 2 3 1 2 3 4 Treating Con-ditions of Oily Substance Filtration 50 50 50 30 30 30 25 Temperature (°C.) Holding Time 0 16 40 22 48 0 40 (hr) Quality of Pur- ified BPTMCPurity (%) 99.9 99.9 99.9 99.7 99.4 99.8 99.8 Phenol (ppm) 100 120 1401600 5900 290 400 Na (ppm) 0.4 0.3 0.8 3.7 10.0 2.1 9.1 Cl (ppm) 0.270.5 0.7 10.0 9.9 5.5 3.9 S (ppm) 0.6 0.6 0.6 0.6 0.7 0.6 1.4

1. A process for production of1,1,-bis(4-hydroxyphenyl)3,3,5-trimethylcyclohexane which comprisesreacting phenol with 3,3,5-trimethylcyclohexanone in the presence of anacid catalyst, separating the resulting phenol adduct crystals of1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane from the resultingreaction mixture, and removing the phenol from the phenol adductcrystals, wherein the phenol adduct crystals are dissolved in acrystallization solvent comprising an aromatic hydrocarbon solvent andwater, crystallizing the crystals of1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane out of thecrystallization solvent, and collecting the crystals by filtration attemperature of 40–60° C.
 2. The process as claimed in claim 1, whereinthe crystals of 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane arecollected by filtration at a temperature not lower than 45° C.
 3. Theprocess as claimed in claim 1, wherein the amount of the aromatichydrocarbon solvent in the crystallization solvent is in the range of55–75% by weight.
 4. The process as claimed in claim 1, wherein thecrystallization solvent is used in an amount of 150–400 parts by weightin relation to 100 parts by weight of the phenol adduct crystals.
 5. Theprocess as claimed in claim 1, wherein the aromatic hydrocarbon solventis at least one selected from the group consisting of benzene, toluene,xylene and ethylbenzene.
 6. The process as claimed in claim 1, whereinthe crystallization solvent consists essentially of an aromatichydrocarbon solvent and water.